Class Missing

Lib/test/test_ordered_dict.py:270–272

        # make sure pop still works when __missing__ is defined
        class Missing(OrderedDict):
            def __missing__(self, key):
                return 0
        m = Missing(a=1)
        self.assertEqual(m.pop('b', 5), 5)
        self.assertEqual(m.pop('a', 6), 1)